"I have considerable sympathy for the family of Mr Renton, who face an incredibly difficult situation. Understandably they want to do the best for their son, and they believe that this option is worth trying."

Mr Dunne said he had also considered the absence of any other treatment options, the low risk of significant adverse effects, and the hospital ethics committee's recommendation.

"Ministerial approval in this case does not extend beyond Mr Renton's application and should in no way be construed as setting a wider precedent."

Mr Dunne said he was satisfied with the way the DHB and the Ministry of Health had handled the matter, and that he hoped for a good outcome for Mr Renton and his family.

Alex Renton's mother Rose told Checkpoint she was informed of the decision this afternoon just before the news was made public.

She called Mr Dunne's decision fantastic.

"Each day's a new day and today's a great day for Alex and the family," she said. "It's exciting that the minister is prepared to accept it on compassionate grounds, and that's what we were hoping for."

Ms Renton said it would take just less than a week to get the medication to Alex.